The "Manual of Oil and Gas Terms" by Williams and Meyers, Seventh Edition (1987) defines a stabilized liquid hydrocarbon as:
"The product of a production operation in which the entrained gaseous hydrocarbons have been removed to the degree that said liquid may be stored at atmospheric conditions. 16 Tax Admin. Code .sctn.3.36(b)(2)."
When the production operator has a CO.sub.2 flooding operation, the liquid hydrocarbon condensate that is produced contains CO.sub.2 as a volatile component in addition to the entrained gaseous hydrocarbons. In addition, hydrogen sulfide (H.sub.2 S) can also be present when the hydrocarbon condensate is produced from a "sour" well. It is important to remove the normally gaseous hydrocarbons (e.g., methane, ethane, propane, iso-butane), CO.sub.2, H.sub.2 S, and any other volatile components from the liquid hydrocarbon condensate in order to obtain a stabilized condensate that can be safely and conveniently stored and processed at atmospheric conditions. It is also important to stabilize the liquid condensate in a manner that permits recovery of the volatile components in order to maximize the economics of the process.
The problem of stabilizing liquid hydrocarbon condensate in an economic manner is not new, of course, and many methods have been described in the literature for stabilizing liquid condensate. The following patents are illustrative:
U.S. Pat. Nos. 4,459,142 and 4,466,946 describe processes for separating carbon dioxide and other volatiles from a hydrocarbon stream. One or more stabilizer columns was utilized in both instances to separate the natural gas liquids (NGL) from the gaseous components. Condensate knocked out during processing of carbon dioxide-rich gases associated with EOR projects requires special handling so that a stabilized condensate can be produced that will meet sales product specifications normally based on a Reid vapor pressure close to atmospheric pressure. Stabilization of the condensate requires removal of not only carbon dioxide but also light hydrocarbons (i.e., methane, ethane, propane and isobutane). The heavier hydrocarbons (i.e., n-butane-plus fraction) is recovered as stabilized condensate in the bottom product of the fractionator. The overhead vapor product from the condensate stabilizer can be further treated for removal and recovery of carbon dioxide for injection while the hydrocarbons can be further processed in a gas plant. For a total or partial fractionator to be utilized to obtain the necessary condensate stabilization, typical designs require two fractionators to operate in series with the overhead temperature of the first column to be below zero in order that reflux requirements can be achieved. With temperatures at this level, water removal of the feed stream is necessary to prevent hydrate formation within the column.
U.S. Pat. No. 3,244,600 describes an apparatus for removing volatile hydrocarbons from raw streams of liquid petroleum and U.S. Pat. No. 2,367,862 describes a method of stabilizing gasoline, a multicomponent hydrocarbon liquid. These patents are incorporated herein by reference. In spite of the progress that these inventors may have made to the arts and useful sciences, there still exists a need for an economic method and apparatus for stabilizing liquid hydrocarbon condensate, particularly condensate containing CO.sub.2 and/or H.sub.2 S.